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Feb. 17. 1925.

R. N. GARDNER TIME CALCULATOR Filed Jan. 15, 1924 INVENTOR 7d BY ATTORNEYS 4 rolls.

Patented Feb. 17, 1925.

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Application filed January 15, 1924. Serial No. 686,407.

To all whom it may concern:

Be it known that I, RICHARD N. GARDNER,

a citizen of the United States, residin at city and county of San Francisco, andtate of California, have invented certain new and useful Improvements in Time Calculators, of which the following is a specification. My invention relates to the class of sliderule calculators, and is particularly adapted for calculating elapsed time.

The principal object of my invention is to provide aconvenient device for calculating railway train schedules. Such schedules may extend over a continuous period of several days, slide-rule calculators cover such a period, they-must either be made unduly long, or the graduations must be so close together as to prevent accurate reading to the necessarytime intervals. A calculator embodying my present invention, however, may be made to cover the necessary period of several days, with sufficiently spaced graduations, and yet be of convenient and practicable length.

My present invention constitutes an improvement on the time calculator for which Letters Patent No. 1,458,649 were granted to me under date of June 12, 1923, in that, in addition to the use set forth above, it may also be employed for calculating the elapsed time and over-time of workmen. For this reason it is of particular advantage in railway ofiices, in that the same device may be used for calculating train schedules, over any ordinary period of time; for calculating the elapsed time, for pay-roll purposes, of, train men; for determining the hours at which train men ma be called for or relieved from duty; and or calculating the over-time of train men in figuring pay- It is to be understood, however, that my device is not limited to the uses described above, but may beemployed for determining the time and-over-time of emplo ees in any industry, or for calculating the e? between any two known limits for any purpose whatsoever. Moreover, although my invention is herein described and illustrated in its referred form, it is to be understood that cl iangesmay be made in the form and construction of the device within the scope of the claim hereto appended.

My invention will now be fully described with reference to the accompanying drawand in order to make theusual apsed time.

ing, wherein the figure is broken, of my time calculator.

In the drawing, the reference numeral 1 designates a body, in which is mounted, in any well known manner, a longitudinally movable slide 2. A marker 3, extending transversely across the body 1, is also longitudinally movable thereon, being mounted for'such movement in any convenient and well known manner not shown in the drawings. 1

The body 1 is provided with a scale 4 indicating time as expressed by the clock, and extending for twenty-four hours, from midnight to midnight. Thus the first half of said scale 4, from its left hand end to the center, is A. M. and the second, or right hand end is P. M. If desired, the figures of the first half of said scale can be printed in light-face type, and those of the second half in dark face type, to differentiate between A. M. and P. M. In the particular rule shown in-the drawing, the unit value of the clock scale 4 is ten minutes, but this may be varied to suit the requirements of the use for which the It is preferable to have the scale 4 equidistant from the ends of the body, but such positioning is not essential. Likewise, the total length of the body 1 ma be varied to suit convenience, but I pre er to make, it twice the length of the clock scale 4, for thereason, that it then coincides with the length ofthe slide 2, which must be twice the length of said clock scale 4. The total length of the vparticular rule shown in the drawing would therefore be twenty-four inches, each hour on the clock scale 4 being measured by one-halfof an inch.

The slide 2 is provided with a plurality of elapsed time scales, there being five such scales shown in the drawings, and designated by the reference numerals 5, 6, 7, 8 and 9 respectively. These elapsed time scales are positioned one below the other, as shown,and the spacing, as well as the unit value, of their graduations are-the same as those of the clock scale 4, each mark representing ten minutes. For convenience in readin I refer to arrange the figures of each e aps time scale one above the other, the two lower figures representing minutes and those above representing hours, and said figures are placed .to the left of the line to which they refer. Thus for exam Ie, the figures appearing in the scale 9 a plan. or; face view,

. mediately to l the enough of such figures to illustrate the oper ation of the device.

The uppermost elapsed time scale 5, near- 'estthe clock scale 4, begins with zero at a" suitable zero-mark 10 at the longitudinal center of the slide 2, and extends continuously to twent four hours at'the right hand end of said s ide. -The next lower scale 6 1 begins with'zero at the lefth'and end of the slide and runs'continuously to 48 hours at with 24 7 hours,

its ri ht hand end. The succeeding scales 7,

Sand 9 also extend the full length of the slide, beginning at the left, respectively, 48 hours, and 72 hours, and ending respectively with 72 hours, 96'hours, and 120 hours. It will be seen, therefore,

that the value of any given mark on any one of the scales 6, 7, 8, or '9, is twenty four hours greater than the value of the corresponding mark on the scale lmmedlately above. A

, This arrangement of the scales 5, 6, 7, 8 and 9 enables the calculation ofelapsed time over a period of as much as five days, withsli e 2 is set so out necessitating the use of a rule of impracwith unduly close 1e, to ,find the time .M. and 8:30PM,

ticable length, or one graduations. For exam ela singbetwe'en 10:30

' cides with the 10 A. M. mark on the clock scale 4, and themarker 3 is then set so that its left hand edge coincides with the 8:30. P. M. mark on said scale 4, as-shown in the drawing. The figures wanted, 10 hours, will then appear in the scale '5 immediately to the left of the marker 3. If the elapsed time is wanted from 10 :30 A. M. of one day to 8 :30 P. M. of the followin or second day, the same settings of the side 2 and marker 3 give the result, 34' hours, in the scale 6; and if theperiod extends to the same hour on the third, fourth,or fifth day, the result will be found, withthesa'me setting, in the scales 7,

8 or 9 respectively. "It is to be noted that the efi'ectof the scales 6, 7, 8 and 9 is toadd the 'total value of thefixed clock scale 4, or twent -four'hours, to whatever result is ob-- taine The scales 4,5, 6, 7, 8 and 9may be appr'opriately designated on the marker 3, as

shown, by thelegends Clock, 1st Day, 2nd

Day,- etc.

At the lower ed eof the slide 2 is a scale 11, which may be designated by the words Inflated Time upon the marker 3. Said scale 11 is used in figuring the over-time of employees, for pay-roll or other purone hundred eight hours can.

that the zero-mark l0 coinfrom the first elapsed'time scale '5.

poses, and is so designed as-to give an apparent value for the over-time, which value he added directly to the elapsed time and the sum multiplied by the straight time :wage rate to give the total wage due the employee. In the particular device illustrated, the inflated or over-time scale 11 is designed for employees reoeivin ,time and one-half, or a 50% increase," or time over eight hours. If a different percentage ofincrease for over-time is paid, or if the inflated rate begins aftera different period, t'hegcale 11 mustbe given a'value different from that shown, as will be later explained, but the principle of the valuation of said scale 11 is the same in all cases. When the same calculator isv to be used for figuring pay-rolls of different classes of employees receiving over-time pay under different condition's, a number of slides 2may be pro vided, identical in all respects except in the valuation of the scales 11. It would then be necessary only to change from one slide to another when changing from one class of employees to another.

' The 'graduations on the over-time scale 11' are spaced to -correspond with those of the other scales in all cases. The unit value of the scale 11, however, is related to the unitvalue of the'other scales as the excess wage rate for over-time is related to the straight time or basic wage rate. Thus in the specific instance shown, the unit value of the'scale 11 is 50% of that of the other scales, orfive' minutes-,- and'thi valuation is adapted for use only in cases where the over-time wage rate is 50% greater than the straight time rate. If the over-time rate is double-time, or an excess over the straight time rate of 100%, then the unit value of the scale ll must be 100% of that.

of the other scales, or ten minutes.

The inflated time scale 11 begins in line with the eight hour mark on the first;

over-time wage is to be paid after eight-v elaps'ed'time scale 5, l as shown, only'if the hours ofwork. If overtime is'to be paid after nine hours of work, then'the scale 11- would begin in line with the nine hour mark on said scale 5, and for other conditions accordingly. For convenience, when using the device for calculating'from P. M. to A. M. instead of from A. M. to P. M. as shown, I provide a second portionll of the scale '11, hearing thesame relation to the.

second day scale '6 aslsaid scale ll bears to the first day scale 5. I

As an example of the use of the inflated time scale 11, the illustrated settings of the slide 2 and marker '3 may be used to, calculateithe wage due an employee who works from 10:30 A. M; to 8 :30 P. M. The elapsed time, as given by the scale 5, is ten hours. The apparent over-time, as given by the scale 11, is one hour, which must be iius added to the elapsed time and the sum multiplied by the strai ht timerate to arrive at the total amount ue. Obviously, the result is the same as that arrived at by multiplying eight hours by the straight time rate, then multiplying the difference between ten and eight, or two hours, by the over-time rate, and adding the two results together, but the method involving the use of my apparent over-time scale 11 has the advantage of necessitating only one multiplication, at the straight time rate. It is to be noted moreover, that, by the use of my device, the straight time and over-time can be kept separate, as is common practise in railway statistics.

Apart from the specific use of my calculator as described above, it will be seen that the function of the first elapsed time scale 5 is to indicate the arithmetical difierence between any two given points on the fixed scale 4, and that the function of each of the other elapsed time scales 6, 7,. 8, and 9 is to add a pre-determined quantity, or more specifically the total value of the fixed scale 4, to whatever result is obtained. from the elapsed time scale immediately above. The

function of the inflated time scale 11 is to indicate, in terms of a pro-determined coefiicient (in the specific instance shown, 50%) the difierence between a fixed point and any other point on the elapsed time scale 5.

This latter function is similar to that described in In said previous Patent No. 1,458,649, the lmprovement residing in making the scale 11 as an integral part of the slide 2, thereby simplifying the construction of the device by reducing the number of movable parts.

I claim:

A time calculator comprising a body member having a fixed scale representing a period of time and divided into units of equal value; and a slide having a plurality of scales of the same unit value as that of said fixed scale, the first of said movable scales beginning with zero at the longitudinal center of said slide and extending to one end thereof and having a total value equal to that of said fixed scale, and each of the succeeding movable scales beginning at the opposite end of said slide with a value equal to that of the preceding scale at the center of said slide and extending the full length thereof, and said slide having two further scales each beginning with zero at points bearing a predetermined relation respectively to the first and second movable scales and advancing by units whose value bears a predetermined relation to the unit value of the first mentioned movable scales.

In testimony whereof I have signed my name to this specification.

RICHARD N. GARDNER. 

